1. Field of the Invention
This invention resides in the field of laboratory apparatus for chromatographic separations of liquid samples. This invention is particularly concerned with packed-bed column cartridges and their method of manufacture.
2. Description of the Prior Art
Packed-column chromatography is widely used in clinical laboratories and research laboratories by virtue of its ability to separate components of liquid samples from many sources and for many reasons. As both an analytical tool and a diagnostic tool, packed-column chromatography offers a means of providing rapid determinations with a minimum of effort and sample preparation. As in all analytical and diagnostic methods, the value of packed-column chromatography is greatest when a large number of samples are to be analyzed under the same criteria or for comparison with each other or with a standard. The optimal packed-column chromatography system is therefore one that produces separations quickly and in a reproducible and reliable manner. This requires standardized conditions which include a high degree of control over the packing volume, the packing density and the flow pattern of the sample and carrier liquid through the packing. These qualities are all enhanced when there is minimal opportunity for user error.
The need for speed, uniformity and reliability has led to the development of column cartridges or pre-packaged disposable columns, which are manufactured by mass production, purchased in bulk, and used either once or a limited number of times before being discarded. The use of cartridges that are packed by the manufacturer sharply reduces the opportunity for user error, and offers the standardization and uniformity that comes with high-volume manufacture and mass production techniques. Nevertheless, prepackaging shifts the error to the manufacturing process, where opportunities for error and variability still exist. Such factors as the inattentiveness of individuals in the manufacturing plant and changes of manufacturing personnel can introduce nonuniformities into the product, and in any event, the cost of labor remains a factor, particularly when a precision product is sought.